US President George W. Bush has lunch with United States Marines at the Marine Corps Base Quantico in Quantico, Virginia, 14 September 2007.

Here is the transcript of President Bush's weekly radio address today:

THE PRESIDENT: Good morning. This week, General David Petraeus and Ambassador Ryan Crocker testified before Congress on the progress of America's strategy in Iraq, including the surge in forces. They agreed that our Coalition faces formidable challenges. Yet they also said that security conditions are improving, that our forces are seizing the initiative from the enemy, and that the troop surge is working.

Because of this progress, General Petraeus now believes we can maintain our security gains with fewer U.S. troops. He's recommended a force reduction of 5,700 troops in Iraq by Christmas, and he expects that by July we will be able to reduce our troop levels in Iraq further, from 20 combat brigades to 15. He's also recommended that in December we begin a transition to the next phase of our strategy in Iraq, in which our troops will shift over time from leading operations to partnering with Iraqi forces, and eventually to overwatching those forces.

I have accepted General Petraeus's recommendations. And I have directed that he and Ambassador Crocker deliver another report to Congress in March. At that time, they will provide a fresh assessment of the situation in Iraq and of the troop levels we need to meet our national security objectives. The principle that guides my decisions on troop levels is "return on success." The more successful we are, the more troops can return home. And in all we do, I will ensure that our commanders on the ground have the troops and flexibility they need to defeat the enemy.

Anbar Province is a good example of the progress we are seeing in Iraq. Last year, an intelligence report concluded that Anbar had been lost to al Qaeda. But local sheiks asked for our help to push back the terrorists -- and so we sent an additional 4,000 Marines to Anbar as part of the surge. Together, local sheiks, Iraqi forces, and Coalition troops drove the terrorists from the capital of Ramadi and other population centers. Today, citizens who once feared beheading for talking to our troops now come forward to tell us where the terrorists are hiding. And young Sunnis who once joined the insurgency are now joining the army and police.

The success in Anbar is beginning to be replicated in other parts of Iraq. In Diyala, a province that was once a sanctuary for extremists is now the site of a growing popular uprising against the extremists. In Baghdad, sectarian killings are down, and life is beginning to return to normal in many parts of the city. Groups of Shia extremists and Iranian-backed militants are being broken up, and many of their leaders are being captured or killed. These gains are a tribute to our military, to Iraqi forces, and to an Iraqi government that has decided to take on the extremists.

The success of a free Iraq is critical to the security of the United States. If we were to be driven out of Iraq, extremists of all strains would be emboldened. Al Qaeda could find new recruits and new sanctuaries. And a failed Iraq could increase the likelihood that our forces would someday have to return -- and confront extremists even more entrenched and even more deadly. By contrast, a free Iraq will deny al Qaeda a safe haven. It will counter the destructive ambitions of Iran. And it will serve as a partner in the fight against terrorism.

In this struggle, we have brave allies who are making great sacrifices to defeat the terrorists. One of these Iraqis was a man named Sheikh Abdul Sattar. He was one of the tribal leaders I met on my recent visit to Iraq, who was helping us to drive al Qaeda out of Anbar Province. His father was killed by al Qaeda in 2004. And when we met Sheikh Sattar, he told me, quote: "We have suffered a great deal from terrorism. We strongly support the democracy you have called for." Earlier this week, this brave tribal sheikh was murdered. A fellow Sunni leader declared: "We are determined to strike back and continue our work." We mourn the loss of brave Iraqis like Sheikh Sattar, and we stand with those who are continuing the fight.

If Iraq's young democracy can turn back its enemies, it will mean a more hopeful Middle East -- and a more secure America. So we will help the Iraqi people defeat those who threaten their future -- and also threaten ours.